Blood typing slides



Oct. 24, 1961 SHERMAN 3,005,375

BLOOD TYPING SLIDES Filed May 6, 1959 INVENTOR. (Fab A 90 Sl/EfMflA/ ZMM' M ATTOAl/E/ 3,005,375 BLOOD TYPING SLIDES Leonard Sherman, 15340Marlow, Oak Park 37, Mich. Filed May 6, 1959, Ser. No. 811,339 1 Claim.(Cl. 88-14) The invention pertains to slides which are used in medicallaboratories for the purpose of ascertaining the type of a personsblood. This is important in cases of blood transfusion where care has tobe taken that the blood of the donor be of the type compatible with theblood of the patient who is to receive said blood as otherwise thetransfusion might result in an unfavorable reaction or even the death ofthe patient.

The major blood types are known as types A, B, AB and O, and the testingof the respective types of blood is effected by means of said slides inwhich small quantities of blood each mixed with a suitable serum areplaced for examination.

The slides are placed upon a frosted glass of a box-like viewer fromwhich light is directed through the frosted glass against the slides andthe contents thereof. While resting on the glass the slides may berocked back and forth to agitate the contents of the slides in orderthat each sample of blood placed therein may be mixed with a serum addedthereto. While rocking the slides the operator or technologist watchesthe samples for signs of agglutination and clumping. It is particularlyessential in these tests to determine whether agglutination or clumpingoccurs in what is known as the Rh factor consisting of Rh and numeroussub types ofsaid Rh factor.

Used at present by technologists are two types of such slides neither ofwhich is fully satisfactory as each has certain shortcomings as will bepresently explained. One type of the slides is a plain microscopic glassslide which is marked with three rings with a wax pencil to denote theblood types A, B, and Rh This method provides a flat surface for thedetermination of the Rh factor. However, when the view box is rocked,the slides cannot be tilted more than degrees as otherwise the bloodwill seep through the wax markings and spill over to the other types onthe glass slide and in a great number of cases, it will spill over intothe view box making the cleaning of the instrument necessary, andcausing the technologist to repeat the typing process.

Another type consists of a flat glass slide with semispherical cavities.This slide is satisfactory for the major blood types. However, only asmall portion of the blood on the bottom of the slide is heated by theview box and the density of the blood makes the reading of the Rh factordiflicult due to the finer clumps of the Rh agglutination.

To overcome said difliculties and drawbacks, I have produced a slidewhich consists of a flat plate of translucent plastic material and whichis formed with three oval depressions each having a flat bottom. Theflat bottom insures an even heating of the blood for the Rh factor andspreads the drop of blood and typing serum over an area which enablesthe technologist to View the clumping better since the blood is spreadout on the slide. The oval-shaped depression also permits the slide tohe rocked to a considerable angle without spilling over into othertyping wells or into the view box. The increased rocking angle resultsin a faster agglutination of the Rb States Patent 6 Patented Oct. 24,196i IQC factor. The translucent plastic material used in my inventionprovides an improved contrast in viewing the clumping as compared to thetransparent slides now used in present techniques.

Needless to say, the slide also incorporates markers to deter errors inblood typing and the inexpensive disposable feature of the plastic slidewhich is produced at a fraction of the cost of the present slides,eliminates the cost and time in the cleaning and preparation of theslides used in the test and prevents possible contamination which may bepathological in nature if the blood contains hepatitis or otherorganisms.

I shall now describe my slide with reference to the accompanyingdrawings in which:

FIG. 1 is a perspective view of my slide;

FIG. 2 is a perspective view of the slide shown with its bottom up;

FIG. 3 is a top plan elevational view of the slide; and

FIG. 4 is a sectional view of the slide on line 3--3' of FIG. 1.

Similar numerals refer to similar parts throughout the several views.

The slide generally identified by numeral 10 is preferably rectangularin shape and includes a flat top 11 and a marginal flange 12 which isturned downwardly from said top so that as a whole the slide has theform of an inverted tray. Portions of the top are depressed to form aplurality of recesses 13, each of which has the form of an ellipse, andeach of which is defined by a flat bottom 14 and by an upwardly andoutwardly slanting wall 15. The slide shown in the drawings has threesuch recesses which are spaced from each other and which are marked byletters A, B and Rh these markings having a specific significance withreference to the type of blood tested in the slide.

It will be understood that the outline of the respective recesses may bevaried provided that each bottom area has a longer dimension in thedirection transversely to the axis upon which the slides are rocked.

The manner in which the slides are to be used has already been describedherein. The novel aspects of my slide, each of which I consider criticalare as follows:

The slide is to be of translucent material, the recesses are to beelongated in the direction cross wise to the direction of the rocking ofthe slide, and the bottom of each recess is to be flat.

After having described my slide, what I wish to claim is as follows:

A blood typing slide consisting of a flat plate of plastic material, theplate having a plurality of recesses spaced from each other anddepressed below its top surface,each recess having a flat bottom lyingin a plane spaced below said plate, and a continuous marginal flange onsaid plate with its bottom edge substantially coplanar with the bottomsurfaces of the flat bottoms of said recesses.

References Cited in the file of this patent UNITED STATES PATENTS2,041,290 Jackson May 19, 1936 2,302,830 Axelrad Nov. 24, 194-2 FOREIGNPATENTS 739,662 Great Britain NOV. 2, 1955

